Internal wrench



Oct. 4, 1966 J. M. PARKS 3,276,297

INTERNAL WRENCH Filed Nov. 27, 1964 James M. Par/k5 I N V15 N TOR.

ATTGF/WE United States Patent 3,276,297 INTERNAL WRENCH James M. Parks, 3517 Houston St., Corpus Christi, Tex. Filed Nov. 27, 1964, Ser. No. 414,062 2 Claims. (Cl. 81-72) the application thereto of an external wrench to permit the rotation of the fitting by such means.

Wrench from such gripping engagement.

A further object of the invention is the provision of in the other direction to allow the parts to move out of such gripping engagement.

Another object of the invention is to provide an internal wrench for tubular articles which is of simple de sign and rugged construction, capable of withstanding The above and other important objects and advantages of the invention may best be understood from the following detailed description, constituting a specification of the same, reference being had to the annexed drawings wherein- FIGURE 1 is a side elevational view of a preferred embodiment of the internal wrench of the invention, showing the same in a partly expanded condition;

FIGURE 2 is a central, longitudinal, cross-sectional view of the invention as illustrated in FIGURE 1;

FIGURE 3 is a top plan view of a somewhat different form of the invention, in its retracted and unexpanded condition;

FIGURE 4 is a cross-sectional view, taken along the line 4-4 of FIGURE 3, looking in the direction indicated by the arrows; and

FIGURE 5 is an end elevational view of the invention as illustrated in FIGURE 1, looking at the right hand end of the wrench as shown in FIGURE 1.

Referring now to the drawings in greater detail, the internal wrench of the invention, as illustrated in FIGURES 1, 2 and 5 comprises an elongated body 10, of relatively thick-walled tubular structure, formed in two parts 12 and 14, the part 12 being a main body part formed with a head 16 of hexagonal or other suitable shape in crosssection adapted for engagement by a conventional wrench, or the like, by which the body may be rotated.

The body 10 may conveniently be made from one piece of steel or other suitable metal, of hexagonal shape in crosssection, which is cut along a plane parallel to and spaced somewhat radially from the axis of the body, as indicated at 18 for a portion of its length and then laterally, as shown at 20 to form the two parts, the part 14 being movable laterally away from the part 12 when the tool is expanded.

In making the tool, the hexagonal stock may be turned down to form an external, annular, inwardly tapering groove 30 and a work-engaging portion formed with external longitudinal teeth 26. A resilient metal spring 32 or snap ring may be seated in the groove 30 to yieldingly urge the parts toward their retracted positions and to hold the parts against becoming separated.

For the purpose of expanding the parts and holding the same in gripping engagement with the internal surface of is to be rotated, a screw threaded rod or bolt 34 is slidably disposed in the internal bore 36 of the body, which bolt is of somewhat greater length than that of the body. The I end with a nut 38 positioned for engagement with the outer end face of the head 16 to move the rod longitudinally in the bore upon rotation of the nut in one direction in engagement with the head. The rod 34 is provided with a laterally extending key 40 formed therehaving a longitudinally tapering face 42, which is positioned for sliding engagement with the bottom, longitudinally tapered face 44 of an internal longitudinal groove 46 formed in the part 14 to move the parts laterally apart upon longitudinal movement of the rod 34 in the bore 36 when the nut 38 is tightened in engagement with the head 16.

In making use of the wrench, constructed as described above, the nut 38 is backed off from the head 16 to allow the rod 34 to be moved longitudinally in the bore to the right, as viewed in FIGURES 1 and 2, until the key 40 is moved to a position to allow the part 14 to be moved into contact with the part 12 to fully contract the wrench, whereupon the toothed portions of the parts may be inserted together into the tubular article which is to be rotated by the wrench, the head 16 extending externally beyond the end of the article. With the tool thus inserted, the nut 38 is then tightened against the head 16 to pull the rod 34 to the left to wedgingly engage the key 40 with the part 14 in the slot 44 to expand the wrench to grippingly engage the teeth 26 with the internal surface of the article. When the wrench has thus been expanded in the article, a conventional wrench, or other suitable tool may be engaged with the head 16 to rotate the internal wrench and the article therewith.

When it is desired to remove the internal wrench from gagement with the parts to release the parts.

It is to be noted that the part 14 at its inner end extends into a cut-away portion or notch formed -by the laterally extending face 20 and the longitudinally extendrod 34 is provided at its threaded ing -face 18 of the main body portion 12, so that the part 14 will be engaged with an extended surface of the body portion 12, thus increasing the area of contact between the parts to provide a structure of greatly increased strength unlikely to become cracked or broken in use.

A somewhat modified form of the invention is illustrated in FIGURES 3 and 4, wherein the body 10' is formed in one piece having the head 16 and the externally toothed portion 24', and the portion 24 is provided with an external longitudinal slot 44' opening into the central bore 36 and which also extends longitudinally at one end into the head 16. In this form of the invention the rod 34' is formed with an external, longitudinally tapering groove 48 in which a tapered wedge 40 is seated, which wedge is extended laterally into the slot 44 of the body. The wedge 40' is retained in the slot 44' and groove 48 by a resilient element or spring 32 which extends about the body within an external annular groove 30.

The operation of this modified form of the wrench of the invention is similar to that of the form illustrated in FIGURES 1 and 2. The nut 38 is backed-off from the head 16 to allow the rod 34 to be moved to the right as viewed in FIGURES 3 and 4 to allow the wedge 40 to move radially inwardly of the slot 44' so that the toothed portion of the body may be inserted into the object to be turned. When the toothed portion has been inserted in the object the nut 38 may be tightened against the head 16 to pull the rod 34' to the left as viewed in FIGURES 3 and 4 to wedgingly engage the wedge 48 with the rod and article to cause the teeth 26 to be grippingly engaged with the internal surface of the article. With the wrench thus tightened in place the Wrench may be rotated by the head 16 to rotate the article therewith.

In order to release the wrench, the nut 38 may be backed-off from the head 16 land the rod 34 moved tothe right to release the wedge 40' whereupon the wrench may be removed from the article.

The head 16' is preferably of larger size than the portion 24, so that the area of contact between the sides of the wedge 40' and the side walls of the groove 44' of the body 10' is greatly increased to provide increased strength for the transmission of rotative force from the body to the object to be rotated.

The teeth 26 and the teeth 26' of both forms of the wrench are preferably shaped as illustrated in FIGURE 5, wherein the teeth 26 are shown with their opposite faces 23 and 25 of different widths or depths, whereby the teeth present the effect of extending in somewhat angular relation to radii from the axis of the body through the apices of the teeth. By so shaping the teeth an improved gripping of the internal surface of the article to be rotated may be obtained to secure greater application of rotative force thereto in the direction of desired rotation.

It will thus be seen that the invention provides an inside wrench of simple design, which is of strong and rugged construction, and which is easily applied and removed without danger of becoming stuck in the article which it is used to rotate' The invention is disclosed herein in connection with certain specific embodiments of the same, but it will be understood that these are intended by way of example only, and that the invention is capable of substantial variations in structure within the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. An internal wrench comprising an elongated body having a central longitudinal bore therethrough and formed in two separate parts adapted to be assembled in surrounding relation to the bore each having external teeth, means slida'bly disposed in the bore in position for coaction with the parts to move the parts laterally away from each other to expand the body upon longitudinal movement of said slidable means in one direction in the bore and to allow the parts to move laterally toward each other to contract the body upon longitudinal movement of the slidable means in the other direction in the bore and means for moving said slida'ble means in said one direction, said parts having surface portions disposed for facing contact in a plane parallel to and spaced radially from the axis of the body and other surface portions disposed for facing contact in a plane normal to said axis, when the parts are in fully retracted positions.

2. An internal wrench comprising an elongated tubular body formed in one piece, having a wrench engaging head at one end and a generally cylindrical end portion at its other end formed with a radially extending longitudinal slot extending at one end into said head, external teeth formed on said cylindrical portion, wedge means movably disposed in the body for radial movement in the slot to one position in engagement with the internal surface of a tubular article surrounding the body to grippringly engage said external teeth with said surface, and to another position out of such engagement, a longitudinally slidable element in the body positioned for coaction with said wedge means to move the wedge means radially outwardly of the body upon movement of the element in one direction and to allow radial movement of said wedge means inwardly of the body upon movement of the element in the other direction, means movably mounted on said element in position for coaction with said element and head to move said element in said one direction, and yieldable means positioned for coaction with the body and wedge means to yielding-1y resist outward radial movement of the wedge means.

References Cited by the Examiner UNITED STATES PATENTS 1,992,474 2/ 1935 Currier 81-72 2,226,078 12/1940 Spahn 8172 2,719,747 10/1955 Layne 81-72 2,914,330 11/1959 Wheeler 279-2 3,181,396 5/1965 Nance 8172 WILLIAM FELDMAN, Primary Examiner. G. WEIDENFELD, Assistant Examiner, 

1. AN INTERNAL WRENCH COMPRISING AN ELONGATED BODY HAVING A CENTRAL LONGITUDINAL BORE THERETHROUGH AND FORMED IN TWO SEPARATE PARTS ADAPTED TO BE ASSEMBLED IN SURROUNDING RELATION TO THE BORE EACH HAVING EXTERNAL TEETH, MEANS SLIDABLY DISPOSED IN THE BORE IN POSITION FOR COACTION WITH THE PARTS TO MOVE THE PARTS LATERALLY AWAY FROM EACH OTHER TO EXPAND THE BODY UPON LONGITUDINAL MOVEMENT OF SAID SLIDABLE MEANS IN ONE DIRECTION IN THE BORE AND TO ALLOW THE PARTS TO MOVE LATERALLY TOWARD EACH OTHER TO CONTACT THE BODY UPON LONGITUDINAL MOVEMENT OF THE SLIDABLE MEANS IN THE OTHER DIRECTION IN THE BORE AND 